(Topic ID: 127492)

TZ Switch matrix overvoltage problem


By WannaPinball

4 years ago



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#1 4 years ago

Diagnosing a confusing switch matrix issue.
On a TZ, the U20 chip (2803) will blow after a few plays.
Hence, with all connectors plugged in, we are finding some overvoltage on a few of the rows (white wires). But none of the columns (green wires)

Most lines, such as the green wire connectors, are at approx 11.5volts but a few of the white wire leads for rows, are as high as 13.9volts
So unpluging a number of connectors to find which ones allow the voltage to drop has narrowed it down to the OPTO switch circuits being suspect.
(Note that NO change observed for disconnecting Lamp, Coil or Flasher circuits.
and all underplayfield micro and leaf switches inspected for shorts.
Also, as information, CPU, Power Driver and 10-opto boards have been serviced.)

So, overvoltage is the problem.
General Question: Is a reading of 12.5volts tolerable?
Apparently so, as I measure some voltages on a STTNG, at least one of the circuits is at 12.6volts.
Can anyone confirm for sure considering the general "plus or minus 10% tolerance" principle for components?

Next, disconnecting all the opto sensors connectors under the playfield, I see a drop to the 12.5volt level and then reconnecting certain ones (2 or 3) will then increase back to 13.5+volts.

Question: So what about the simple Opto sensors could raise the voltage? Only a short or some other failing of components? (Apparently this game took hit during a lightning storm)
No voltage change when plugging the clock opto connector but the Power miniplayfield is one that boosts the voltage back up. I have yet to check for pinched wires, etc under that playfield.

Any helpful thoughts would be most appreciated. Other questions to clarify are welcome to help all learn from the discussion. Thanks.
- Paul

#2 4 years ago

The voltages you are reading are actually pulsed, so the only completely valid way to test them is either with a scope or logic probe. If the signal is locked on (rather than being pulsed) you will get high readings.

Since the reading you get when using a DMM on a pulsed circuit can vary wildly, depending on the quality of the DMM, it is impossible to say if 12.5 volts is ok. About all you can get with this method is relative readings when comparing different circuits. I would check all of the column readings at J206 and see if they read the same.

Since U20 (column driver) is blowing I'm not sure the row voltages are even relevant since there is a blocking diode on each switch. Although something could be over-driving the chip.

Which columns quit working when the IC blows? At the moment I would be more suspicious of high voltage getting shorted to one of the columns.

#3 4 years ago
Quoted from terryb:

Which columns quit working when the IC blows. At the moment I would be more suspicious of high voltage getting shorted to one of the columns.

...and so would I. It's a matter of particular game play that might be inducing the issue.
--
Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The Place to go for Pinball Repair Info

#4 4 years ago

Thanks for the explanations ... so it seems my approach may be flawed, understood.
So after reviewing this, I decided to test if the chip is truly getting damaged. I never pushed it since bringing into my shop ... it only happened before at the owner's home. But as you will see here, the problem remains.

BTW - Isn't J205, mentioned above the dedicated switches for the coindoor test buttons and coin drop switches? I thought the J206/207 was for columns.

In any case, if the game sits powered on for 15 min, apparently it seems OK.
and while it is OK, I was able to test all the J205 lines and ALL 8 read consistently as between v11.77 and v11.8

I decided to be sure of what I am dealing with, I plugged everything back and measured the "relative voltages" on J206/207 and they measured 11.7ish steadily with my Fluke115 DMM.
BUT for J208/209 ... Pins 9 read at v13.8ish and Pin 8 at 14.02 volts! The rest read safely around 12 volts. (I observed no fluctuation of the readings...is that a due to the quality of the meter?)

So I start a game and after about 5 min, things go crazy. ... the 12 volts was lost.
(I never entered the mini powerfield.)
F115 blew and I tried to replace it to see "which columns quit working", as suggested above.
However, the fuse immediately blows when turning on the power and it won't allow entry into the switch test menu.
I then replaced both U20 and F115 and now the game powers on OK...and it's been sitting for over 15min now with no crazy events.

Regarding 'identifying a particular game play' type is not easy to identify. Do you mean triggering certain switches or playing it hard with flippers or something like that?

Keeping on plugging along...

#5 4 years ago
Quoted from WannaPinball:

Isn't J205, mentioned above the dedicated switches for the coindoor test buttons and coin drop switches? I thought the J206/207 was for columns.

Sorry about the type, yes J206/207.

Quoted from WannaPinball:

Regarding 'identifying a particular game play' type is not easy to identify. Do you mean triggering certain switches or playing it hard with flippers or something like that?

Firing all of the solenoids in test would be a good start.

#6 4 years ago

ok ... I unplugged all the Lamp Matrix related connectors (J133-J137)
and just played a 15 min game including Lost in the Zone (yes, I had the glass off
Plenty of flasher and coil action ... all optos worked fine. But I will test more.
So, I will try again tomorrow to see if it still behaves.

Then the fun of tracking this down.
I did measure the suspicious J208/209 I have been commenting on (white wires) where pin 8 was 14volts high ... it is now only 11.5volts.
The pin 9 remains unchanged at 13.7ish.
The rest are down to 11.7ish.

Interesting...

#7 4 years ago

When you say 14 and 13.7 volts, then there pops up a color in my head, Gray-Yellow.
That is 12V unregulated from J116/117/118-2
Possible contact between Gray-Yellow (12Vunr.) and White-Gray (sw.row 8 ) wires !?

#8 4 years ago

Interesting point on sharing the 12v unregulated ... no issues around the boards/connector area but I may need to look deeper in the harness.
Trying to get back to this project ... among all the others I have.
It's only the one line - J208/209 - pin 9 that remains high at 13.8ish volts in attract mode.
Even with everything plugged back in, all other lines are around 11.5-11.6volts.
So what switches are on that white grey line -
Outhole, Rocker kicker, Left inlane, Lower left 5mil, slot kickout, Lower Rt 5mil, Lower lock, Clock hour

I will assume that the clock has no issue since unplugging the opto connector does nothing to change the voltage. The rest...hmmm...We will see.

#9 4 years ago

You could disconnect the 12Vunr. playfield supply, located on J116,117,J118.
Leave the one with 3 thick wires in place and remove the other 2.
Do you still have 13.8 volt on White-Gray ?

This way you may have a direction to search for.
-If it stays 13.8 Volt then have to search for an other cause.
-If its gone, have to follow all Gray/Yellow wires.

2 weeks later
#10 4 years ago

ok ... back from a trip and hoping to tackle this further. June 5th

Everything plugged in gives about 13.76v on White-gray.
So, I am testing by unplugging 12v J116,J117,J118 ...
Results: 2 connectors - not the thick grey wires --> the voltage goes down to 13.1v
Pull the thick connector and --> the voltage goes down to 11.76v ... equal to all the other white switch wires
Reconnect the thick 12v --> the voltage goes down to 13.1v

One of the other 2, reconnect and no change.
The other of the "other 2 thin Gray/Yellow wire" , I hear a slight snap/crackle as I connect and the voltage goes back up to 13.76v ... so I will begin tracing that circuit.

1 week later
#11 4 years ago

Interesting situation, the way you describe it sounds like the problem is indeed a connection between 12Vunr and switch-column8.
But if the voltage comes back to normal on C8 when the one with the thick wires is disconnected (display goes OFF?), the short may already be found in the backbox.

#12 4 years ago

(June 20th) Finally spent some time tracing the 12v gray/yellow wire through the harness and saw what devices it supplied voltage too.
These included the clock, the 10opto board, the 2 eddy sensors for the powerball and a couple of other connectors.

Unplugged all and saw that the voltage went down to a tolerable 12.46v on the White/gray switch wire.

Everything plugged in would leave the voltage unchanged EXCEPT for the 10-opto board.
(Great, it just had to be the biggest trunk of wires!)

So, the large looped connectors, slipping it on with power on, I think I heard the same little snap/crackle as mentioned above.
Then with the power off, I unplugged all 4 of the other connectors, leaving the looped input connector and the voltage did not jump, still at 12.46v. I am assuming this means that the 10-opto board is not the cause. This 10-opto board was completely rebuilt by Clive.

Then, with the power off, I tested with 2 sets connected. First 2 right side and then 2 left side...
Results: Each of these tests would raise the voltage measurement to 13.5v.

So more tracing needed to see which opto circuit is causing this situation.
Thanks for any comments.
- Paul

#13 4 years ago

Sounds like you're on track. Just keep narrowing it down.

1 week later
#14 4 years ago

(June 29) Time keeps moving.
Update: I explored each destination OPTO off the 10Opto board to find out which switch is causing the voltage to rise.
Out of the 8 connectors along the circuit ... 3 of them raise the voltage and 5 do not.
Without these 3 plugged in, the reading is 12.5v which I believe is tolerable.
Then connecting one at a time:
1 - the connector to the ball lock area ... 2 optos there - rises to: 12.9v
2 - the ball popper that feeds the gumball machine ... only 1 opto set - rises to: 12.6v
3 - the connector to the mini playfield ... only 1 opto set - rises to: 12.9v

1 and 2 = 12.9 - 1 and 3 =13.1 - all 3 = 13.3
This is with the game in attract mode ... not sure if it would rise during gameplay.
Obviously, I have to disassemble areas to examine.

Now, what might happen with opto transmitter/receivers to make voltage rise?
Hmm...I have heard of a leaking opto, is that relevant?

Thanks.

#15 4 years ago

Just throwing this out there. Is it possible that someone in the past replaced some of the opto transmitter/receivers with a wrong type, which might have a smaller voltage drop than normal? Just a shot in the dark. So often I find that weird problems like this are a direct result of something done incorrectly in years previous. Good luck with your problem. I'm glad I'm not having to troubleshoot this one!

#16 4 years ago
Quoted from LOTR_breath:

Just throwing this out there. Is it possible that someone in the past replaced some of the opto transmitter/receivers with a wrong type, which might have a smaller voltage drop than normal? Just a shot in the dark. So often I find that weird problems like this are a direct result of something done incorrectly in years previous.

Good thought LOTR_breath--it is a weird problem.

#17 4 years ago

(July 4) So after fiddling for a couple of hours, I decided to leave the powerfield optos unplugged (2 sets actually...one at the exit where he laughs when triggered and the other at the goal area...just produces some sound fx.) This allowed me to play 3 long games...tolerable voltage at 12.9, I assumed. The game played fine, except he would laugh on exit and at least one pop had to hit on the way down or else because the flippers are disabled while on the powerfield, it would drain but serve the ball back as a ball saver. No real need for the sound fx triggered by the top/goal optos.

HOWEVER, then I measured after the 2nd game and found the white/gray measuring the normal 11.68v.
Then I played a 3rd game and measure after that and saw the voltage back up to 13.46v.
Why? ... I asked myself.

Turns out that if there is ONE ball locked in the lower lock (micro switch, not an opto), then the voltage drops to 11.68 just like all the other switch rows. So, I plugged in ALL the connectors and only put a ball in the lower lock and it maintained a normal ~11.6v ... taking it out made it jump to ~13.5v.
This micro switch is the same type as at the outhole. And it resides on the white/gray row.

SO...I hope to change this switch and maintain the 11.6v.
What kind of explanation would explain this?
There are many spots of corrosion around the game ... I believe it was used
around the shore area for it's lifetime, so possibly affected by salt in the air?
So could something internal to the normally open switch cause this 2 volt jump in the switch circuit?

STRANGE QUESTION: I was curious if it was an reimport and noted that the 2 manufacturing labels specify AMPS = 60 rather than the usual 5 (for export) or 8 (domestic). First time I have seen this. Is it common and explainable?

Comments are most appreciated.

#18 4 years ago

or just the diode? which I will change first

#19 4 years ago

Here is the label inside the cab ... looks like a typo where they switched the Amps and the Hz values.
TZ_AmpsTypo.jpg

#20 4 years ago

Well, it's not the diode and when I take the switch completely out of the game... it remains at ~13.6v.
Both are Doubled leads and remain connected for the daisy chain to be intact.
So, having them separated with no switch installed ... it jumps to ~13.6v
And connecting with a good diode (white wires get non-banded/green get banded side attached)
then it drop to the normal ~11.6v

So it seems that this would indicate that a new switch would make no difference here.

Very interested in what this could mean.
The switch discussed here is #88 Lock Lower.
In testing if some other switches in the column or row make a difference, I found that both optos on the powerfield WHEN BLOCKED would cause the voltage to drop a few tenths and jump back up when light flows across.
So far only this one micro switch seems to make the 2volt difference.
Hmmm...

#21 4 years ago

ok ... turns out that engaging any switch on the white/gray row #8 will lower the voltage to ~11.6v.
(outhole, rocket kicker, left inlane2, 3 standups and lower lock)
Releasing them puts it back up.

So, If I make a stuck closed situation on just one of the standups ... I guess the game would be safely playable. <grin>

#22 4 years ago

ok ... so now I engaged multiple switches on that white/gray row.
All open ...voltage measures ~13.5v.
Pressing and holding one switch ... voltage drops to ~11.6v.
Then holding other switches at the same time.... each engagement lowers the voltage by about 0.1-0.2v further.
So, holding 6 switches simultaneously lowers it to ~10.9v - (3 standups, outhole, rocket kicker and left inlane 2)

#23 4 years ago

As a side - interesting misprint on your serial number decal.

If your machine actually drew 60 amps, you'd fry your house. The circuit your game is plugged into can't support anything over 15A, usually.

#24 4 years ago

Could be a partial short on the row side of one of the switches or the row circuitry on the board. I would pull the row 8 wire at the cpu row connector, close a physical switch (not an opto) and see if the voltage drops. If it doesn't then it's a board issue.

#25 4 years ago

My domestic TZ has a similar misprint and says 80 amps. I wonder how many labels have this issue?

#26 4 years ago

Terry - not sure what you mean by 'partial short'...something compared to a 'full short'? or do you mean something intermittent?
I'd like to try what you suggest but by 'closing a physical switch', do you mean a switch on that same row or any other row?

===
Something I tried was to impose the 'stuck switch' condition on one of the standups of row 8.
The game played fine for about 7 games and then U20 chip blew, along with the 3/4A F114 fuse. Wanted to get a look at what columns blew up but putting in a new 3/4Amp fuse just blew right away when turning on.
So a new U20 chip was required to keep the fuse intact.

This condition supposedly kept the voltage normal on row 8 and not having one target work was ok. It was a pleasure to play for a bit but then a stab of pain when it failed.

#27 4 years ago

So, as I said, it blew up. Then I remembered that there was more than one row with the high voltage and I checked to find that row 7 was up to ~14v. And closing any of the switches on that row would have it drop right to ~11.7v with the .1 or .2 drop for each additional switch closure.

So as an experiment, I found another Greed standup that is seldom hit and am shorting that to a 'stuck closed' status. The whole row has dropped and so I will play with it this way for now and see if another U20 blows.

All other rows measure around ~12v for now.

BTW - I did try to disconnect just the Row 8 wire and hit various switches...none affected the voltage like other row 8 switches would.
The CPU and PowerDriver and 10-Opto boards have all been recently serviced by Clive.

#28 4 years ago

Let's take a step back. If you're blowing U20 then you've got high voltage shorting to one of the columns. If you still have the defective U20 you can test it the continuity across it and possibly identify which column. Check from each pin on the IC to the ground pin for a short.

#29 4 years ago

ok...taking a breath. Thanks.

I have all 4 U20 - (ULN2803 18-pin) chips that have blown and
did continuity test from pin 9 (ground) across to
pins 10 (+12volt) and 11(column through 18 (column 1) .
Each chip had a different set of shorts:
#1 Pins 10, 16
#2 Pin 10 only
#3 Pins 10, 11, 14, 16
#4 Pins 10, 11, 12, 14
(Tested a new chip and, of course, no shorts exist.)

Hmmm...so what does this indicate with only pin 10 common to all chips?

#30 4 years ago

Not as much help as we would have liked. Pin 10 being common is kind of misleading--just means that once the high voltage came in on a row it also shorted out the 12 volts to ground.

I was hoping to only see one column pin blown out and then we would know more specifically where to look.

pin 11 -- col 8
pin 12 -- col 7
pin 14 -- col 5
pin 16 -- col 3

Do any of those columns coincide with any rows where closing the switch seems to cause problems?

One shot in the dark thing would be to check the pop bumpers for any bare wires or leads that could be shorting high voltage to the switch matrix. I suggest that only because I've seen the issue be pop bumpers quite a few times.

#31 4 years ago

@Terry - Not sure what you mean by "closing a switch seems to cause problems" ... the game played completely correct for a number of games. So, do you mean like phantom events or double switch registering or unusual lighting effects? none of these happened.

I completely inspected the pop bumper area and it is very organized in regards to lamp leads and switch circuit wires. But I will keep that in mind for other projects.

Two previous events that could be making this difficult ...
1) this game apparently was subject to a lightning strike, I was told. So, I made sure the 3 boards were not a question mark by being refurbished.
2) The game has been in salt air by the shore for a good deal of time...enough that there are many spots of corrosion on various metal parts. Could this lead to some tiny continuity within switches? hard to say it would make a difference to grounding a column if no physical crossing of wires. I would think only effect would be intermittent switch event or poor contact, like inside a light socket.

hmmm...

#32 4 years ago
Quoted from WannaPinball:

hard to say it would make a difference to grounding a column if no physical crossing of wires.

I'ts not grounding a column, high voltage is being shorted to the column. I doubt if a switch could cause this issue.

When you have an intermittent short like this there's not a lot of classic troubleshooting (i.e. - taking voltage readings) that you can do. It really comes down to inspection or narrowing down the possibilities. Based on the way the chip blew we can presume the problem is on column 3, 5, 7 or 8.

1. Go through all the switches in those rows looking for a wire or lead that could be shorting to high voltage. Move any nearby mech's by hand since they could be moving a wire and causing the short. While I'm at it I move every diode lead or wire as far away from anything else as possible.

2. Pull the column wires for 3, 5, 7 and 8 and see if the problem goes away. Then add one back at a time until the problem shows up again.

3. You could go into switch test and start closing switches and see if U20 blows. Because of your symptoms I am suspicious the high voltage short is on the row side of the switch rather the column side. Thus the switch has to be closed for U20 to blow. This might help narrow down the issue (this is what I was trying to say above, but didn't word very well).

Chris or zaza, if you're still watching do you have any other ideas?

#33 4 years ago
Quoted from terryb:

Chris or zaza, if you're still watching do you have any other ideas?

If visual inspection doesn't give any results, then taking measurements is next. Maybe this will give some findings:
-Machine 'OFF"
-Multimeter in 'BEEP' function. The DMM has to beep instantly if a short occurs. (some multimeters need a few tenths of a second to react)
-Clip one pen to a Gry-Yel 12Vunreg wire . ( this was likely the source of the problem ?!)
-With other pen, measure all white and green wires of switch matrix, but also all metal parts (not the grounded ones). wiggle with the wires.

Can you take a close-up picture of the 10-opto-PCB + wires? Also in surrounded area

2 weeks later
#34 4 years ago

Been a little while here ... still tinkering. Everyone's thoughts are appreciated!

I got a suspicious feeling about one of the flipper opto boards and installed a new one.
Then I got to play about 25 games! A record before the U20 chip and F115 fuse blew.
Almost had a good night sleep that time
NOTE: This is where I also permanently closed 2 standup switches to knock down the voltage on rows 7 and 8.
So these three changes appeared to extend the playtime.
When I inspected the chip for what circuits were shorted, I noted that ONLY Column 3 was damaged.

Today, I started monitoring the Column 3 a bit and began playtesting ... the chip blew after 1.5 games during Fast Lock multiball.
Inspecting this 2nd blown chip ... columns 5, 7 and 8 were damaged. No consistency!
Terry...I was going to start pulling wires as you suggested but now I am not sure if that would help.
All along, I have been making sure no other contacts by leads or diodes.

@zaza - your test sounds different but I am not sure how to implement.
Are you saying that I am checking for a cross between reg12v and unreg12v?

So then, am I correct in saying that the regulated12v is supplied to the switch matrix
AND the unreg12v is what drives the OPTO switches and that the 2 should not cross?
Hence, if there is continuity between the Gry-Yel and the switch matrix ... it would BEEP. But normally, they should not?

Pictures of the area around the 10opto PCB. Let me know how this might help.

20150718_131903.jpg
20150718_131757.jpg
20150718_131809.jpg
20150718_131819.jpg
20150718_131836.jpg

#35 4 years ago

nice pictures

Quoted from WannaPinball:

@zaza - your test sounds different but I am not sure how to implement.
Are you saying that I am checking for a cross between reg12v and unreg12v?

No, that is not what I meant.
I think there is sometimes a connection with 12Vunregulated and the switchmatrix because you did find 13.9 Volts on the white wires. The white wires (rows) can handle some overvoltage, but once a switch is activated, the column drives are under heavy load. That also explains why it is not always the same column.
So, I meant that you want to measure if there is a direct contact between the 12Vunreg and white wires from the switch-matrix.
Done by turning machine off, one pen of DMM on gry-yel and with the other pen all the white wires.
(btw. not the gry-yel from the flipper coil visible in some of the pictures.)

I took one of your pictures and marked 3 areas, 1 with a damaged lamp matrix wire (red) and the other 2 areas with harness bundled together where due to stress and possible sharp edges of the stands, the insulation of the wire can be cut and connecting each other in a wrong way.
This is the kind of short that do happen sometimes and are difficult to find.

picture (cropped):
tz-short.jpg

#36 4 years ago

I have a question.

Did you - or the owner - recently do some work on this game involving soldering? Maybe a coil or switch wire came off that needed to be resoldered?

The reason I ask is I have seen errant solder fall off a soldering iron, etc, and land on a PCB or other place that can cause an intermittent short.

IMHO, if U20 is blowing violently - as in blowing the top off the chip, etc, then I would strongly suspect coil power is making it's way to the switch matrix. I don't think a short from the 12v unregulated circuit would cause a violent failure of U20.

I think one thing I would try is to use the burn in cycle and let the game run a burn in for a few hours to see what happens. If vibration somewhere is causing a coil power short to the switch matrix a burn in might help to narrow it down.

Michael

#37 4 years ago
Quoted from WannaPinball:

So then, am I correct in saying that the regulated12v is supplied to the switch matrix
AND the unreg12v is what drives the OPTO switches and that the 2 should not cross?
Hence, if there is continuity between the Gry-Yel and the switch matrix ... it would BEEP. But normally, they should not?

Not exactly, but close.
Yes, 12Vreg is used on CPUboard by the 339 comparators and the uln2803.
And the 10-opto-board under playfield is powered by the 12Vunreg.

.......ah, you know what, a picture will explain.
abc.jpg

#38 4 years ago

The ULN2803 can handle up to 50V on the outputs (and up to 30V on the inputs), so the unregulated voltages you are measuring are not an issue unless a short to one of the power rails is present (usually why they blow up).

Any time I hear "lightning" or "sea water", I'd be suspect of any of those boards working correctly, even if a pro went through them. The very first thing I would do is swap out the CPU board and see if the problem persists. This way you can eliminate any possibility that corrosion or other chip damage (pre-driver TTL, etc.) is an issue.

#39 4 years ago

I had a TZ that randomly ate a few ULN2803 chips. Turned out a GI light in one of the slings would short to the switch matrix. It's worth a look.

#41 4 years ago
Quoted from WannaPinball:

This is where I also permanently closed 2 standup switches to knock down the voltage on rows 7 and 8.
So these three changes appeared to extend the playtime.

Could be wrong, but I think the voltage readings are just confusing the issue. In order to blow the chip out like you're seeing it is most likely high voltage shorting to the column. There could be a high resistance short from high voltage to the column and then due to vibration, assemblies moving, etc. the short becomes low resistance and boom your ic is toast.

Quoted from WannaPinball:

Terry...I was going to start pulling wires as you suggested but now I am not sure if that would help.
All along, I have been making sure no other contacts by leads or diodes.

At the moment every switch is suspect. You really need to narrow the issue down to a column and then you've only got 8 switches to worry about. Sometimes you just aren't going to find it visually.

2 weeks later
#42 4 years ago

Getting back to shop projects here ..I care about the problem but it gives me a headache :O
(It is 18 day later! Aug 11)... I believe these last comments from various ones have been enlightening.

Especially Tony's comment about the input voltages being fine for up to 30volts... I needed to know what the limits were.
So, I am more convinced as well that the voltage readings are confusing the issue (per Terry)
And I will study more from zaza's post too.

I will post more over the next week ... thank you all.
This is a stubborn issue.
- Paul

#43 4 years ago

I think the best thing is start to narrow down if this is a board issue. Swap either the MPU or driver board or both over to WhiteWater and see which machine acts up. Then swap the other board if the problem did not move to the Whitewater.

#44 4 years ago

I also been wondering what TZ clock board is installed?
Rottendog, the new Ingo board, or the original clock board set?

#45 4 years ago

Good questions Maniac - The CPU and PowerDriverboard have been fully serviced, especially after having concern about the effect of the lightning strike which is, I am told, when the problem started.

How did you know I have a Whitewater...one of my favorite games?
It's hasn't been setup in a while but I agree, that it might be a good swap test machine.

The clockboard is a single layer with LEDs installed but don't know what brand.
I believe I saw it get damaged when the clock optos were unplugged but could something there really affect the U20 chip?

@Radius118 - the U20 is not blowing up violently...it just takes a hit somewhere and the game starts acting crazy as the 12v switch matrix fuse blows (F115 3/4Amp SB) ... of interest, if the chip is not changed along with the fuse, it blows immediately because of the shorts to ground.

It has been consistent over the past 5 chips that changing the fuse and chip will allow the game to play a few games.
One time it was over 20 games and I exercise all areas of the playfield with my play/test style.

#46 4 years ago

Try replacing U20 and the fuse again (if necessary) and running a cpu controlled burn in cycle. I am curious to see what happens.

#47 4 years ago
Quoted from WannaPinball:

How did you know I have a Whitewater...one of my favorite games?

Well, you do have it in your collection list.

Quoted from WannaPinball:

The clockboard is a single layer with LEDs installed but don't know what brand.
I believe I saw it get damaged when the clock optos were unplugged but could something there really affect the U20 chip?

If you had the clock board for over 2 years, then I would guess it to be a Rottendog. I hope you didn't plug it in while power was on.

#48 4 years ago
Quoted from Radius118:

running a cpu controlled burn in cycle. I am curious to see what happens.

This test is a good suggestion. It should cycle all the motors and coils. I would do this test with the backbox light board opened up. Watch the test run on the DMD and hopefully you will see the fuse blow out in the corner of your eye. I am kind of expecting a motor to be causing the issue. Sure hope this test will help narrow it down. It will cycle through everything fast. It might even be good if you can take a video of it since you may not be able to tell at which time did it blow the fuse.

#49 4 years ago

The TZ driver board is also swappable between the Shadow. Sadly, the MPU is not.

#50 4 years ago

I decided to at least run the burn-in cycle ... 2 hours and no incident. ...for those that were curious.

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